Quarterly Results of Operations (Unaudited) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Notes to Financial Statements [Abstract]
Total revenues	$ 2,570	$ 2,548	$ 2,804	$ 2,714	$ 2,662	$ 2,613	$ 2,605	$ 2,527	$ 10,636	$ 10,407	$ 8,499
Total expenses	3,019	2,409	2,363	2,246	2,409	2,310	2,275	2,179	10,037	9,173	9,020
Income (loss) from continuing operations	(513)	151	325	339	196	248	252	255	302	951	(415)
Income (loss) from discontinued operations, net of federal income tax expense (benefit)	0	(8)	0	0	0	(2)	3	28	(8)	29	(70)
Net income (loss)	$ (513)	$ 143	$ 325	$ 339	$ 196	$ 246	$ 255	$ 283	$ 294	$ 980	$ (485)
Earnings (loss) per common share - basic:
Income (loss) from continuing operations (in dollars per share)	$ (1.73)	$ 0.50	$ 1.04	$ 1.08	$ 0.62	$ 0.79	$ 0.34	$ 0.79	$ 0.99	$ 2.53	$ (1.60)
Income (loss) from discontinued operations (in dollars per share)	$ 0	$ (0.03)	$ 0	$ 0	$ 0	$ (0.01)	$ 0.01	$ 0.09	$ (0.03)	$ 0.09	$ (0.25)
Net income (loss) (in dollars per share)	$ (1.73)	$ 0.47	$ 1.04	$ 1.08	$ 0.62	$ 0.78	$ 0.35	$ 0.88	$ 0.96	$ 2.62	$ (1.85)
Earnings (loss) per common share - diluted:
Income (loss) from continuing operations (in dollars per share)	$ (1.73)	$ 0.47	$ 1.01	$ 1.05	$ 0.60	$ 0.76	$ 0.32	$ 0.76	$ 0.95	$ 2.45	$ (1.60)
Income (loss) from discontinued operations (in dollars per share)	$ 0	$ (0.03)	$ 0	$ 0	$ 0	$ (0.01)	$ 0.01	$ 0.09	$ (0.03)	$ 0.09	$ (0.25)
Net income (loss) (in dollars per share)	$ (1.73)	$ 0.44	$ 1.01	$ 1.05	$ 0.60	$ 0.75	$ 0.33	$ 0.85	$ 0.92	$ 2.54	$ (1.85)